Internal-combustion engine



March 10, 19 31. 551555 1,795,551

' INTERNAL COMBUSTION ENGINE Filed Nov. 26, 1929 2 Sheets-Sheet 1 INVENTOR ATTDRl/EY March 10, 1931. J. H. GEISSE 1,795,551

INTERNAL COMBUSTION ENGINE Filed Nov. 26, 1929 2 Sheets-Sheet 2 I Q Q 5 I FiQZ NVENTOR fin 5 W ATTo R/lzy Patented Mar. 10, 1931 NT OFFICE l 7 JOHN HARLEM GEISSE, OF MADISON, WISCONSIN INTEBNAL-CQMBUSTION ENGINE application. filed November as, 1:129. Serial. No. 409,9aal

(GRAHTEB UKDER THE ACT OF MARCH 3,1883, AMENDED APRIL 30,. 1928; 370 0. G. 757) My invention relates broadly to two cycle internal combustion engines and more particularly to a crankcase scavenging system.

An object of the invention is the provision of a crankcase scavenging system in which the displacement of the scavenge pump is in excess of the cylinder displacement.

In substantially all of the present crankcase scavenging systems the pressure attainable in the crankcase is only that occasioned by the piston displacement. Many efforts have been made to reduce the volume in the crankcase to make the piston displacement as effective as possible, but even 100% effectiveness,

which cannot be properly scavenge a two stroke cycle en ine the displacement of the scavenge pump should be as much as or 50% in excess of the cylinder displacement." Despite the in- 20 herent disadvantages of the present crankcase scavenge systems they-have been very generally used due to their simplicity and low cost. My invention has all the advan ta'ges of the simplicity and low cost of the present day crankcase scavenge systems and in addition can be made to have a displacement in excess of the cylinder displacement as great as desired.

With the above and other objects in view,

the invention consists in the constructiom, combination and arrangement of partsas will be described more fully hereinafter.

Reference is to be had to the accompanying drawings forming a part of this specification,

85 in which like characters indicate corresponding parts throughout the several views, and in which a, k

Figure 1 is a cross section of a single cylin der engine in a plane perpendicular to the axis of the crankshaft and through the center line ofthe cylinder, and 1 I a line 2-2 of Figure 2 is a section on the Pi re 1. fi dferring moreparticularly to tlie drawings, 1 is the cylinder of an internal combustion engine of, the two cycle type having inlet HS 2 and outlet ports 3- controlled by l the PlStOIlA. The numerals-5. is thecrank shaft having full circular; webs 6gfwhich'fhave their inner allow no; more,

attained, is insuflicient. To 0 than a running clearance for the connecting rod 7 The peripheries of the webs are also machined to allow no more than a running clearance in the crankcase 8.

The connecting rod 7 has a circular crankpin end 13 that has no more than a running clearancein the crankcase 8. In addition one face 10 of the connecting rod has a contour such that it has nomore than a running clearance with the surface 9 of the crankcase 8 during the down stroke of the piston. The crankcase is provided 'Wlth an air inlet port 11 provided with a check valve 14 and .an air outlet port 12.

In operation, Whenthe piston is at the top of its stroke all fparts of the crankcase and the lower part of the cylinder are in communication with each other and the air inlet port. This condition obtains during the down stroke of the piston until the crankpin end of the connecting rod has passed the air inlet port. At this time the face 10 of the connecting rod approachesithe face 9 of the crankcase sufficiently close to form a seal at this point. This seal is maintained until the piston reaches a predetermined point in the cycle which may be later than bottom center and, since the crank-pin end of the rod also maintains its seal with the crankcase during this period, it is apparent that that portion of the crankcase volume in communication with the air inlet port is out of. communication with the balance of the crankcase volume and the lower end of the cylinder. This not only reduces the crankcaseclearance volume I to a value less thanlth'at attained in any other design but also adds to the displacement of the piston the displacement of the connecting rod. By proper choice of the diameter of the crank-pinend of the connecting rod and itswidth any desired excess may be obtained; c

'Theeabovedescription and accompanying v drawings comprehend only the generaliand preferred 'embodiment' of my invention and that various'minor changes in details ofcon5'- StruCt1On, -ipr0p0rt1 QI-1 and arrangement: of

; parts maybet resoi tedftowithin the scpfpe -;:t he appendedfclaimsfl-andwithout sacr' cing j-anyfof:the'advantages, of the invention.

of scavenge air L Y \r V The herein described invention may be manufactured and used by or for the Government of the United States for governmental purposes Without the payment to me of any 5 royalty thereon.

What I claim is:

1. In an internal combustion engine, a cylinder, a piston, and a connecting rod, the displacement of which is added to the displacement of said piston during part of the cycle to more effectively scavenge said engine.

2. An internal combustion engine having a plurality of cylinders, a crankcase divided into as many compartments as there are cylinders, and a connecting rod operating in each compartment and dividing each compartment into two chambers during part of each cycle.

3. An internal combustion engine having a plurality of cylinders, a crankcase divided into as many compartments as there are cylinders, and a connecting rod operating in each compartment and dividing each compartment into two non-communicating chambers during part of each cycle.

4. An internal combustion engine having a cylinder, a piston operable therein, a crankcase provided with an air inlet and an air outlet, a crankshaft operable in the crankcase, and a connecting rod, said rod dividing that portion of the crankcase in which the air inlet is seated from that portion in which the air outlet is seated during a part of each cycle.

5. An internal combustion engine having a plurality of cylinders, a crank chamber for each cylinder, a piston operable in each cylinder, an air inlet in each crank-chamber, and a connecting rod in each crank-chamber adapted to seal that part of the chamber havingthe air inlet from the balance of the chamber during part of each cycle.

6. An internal combustion engine having a plurality of cylinders, a piston operable in each cylinder, a crank-chamber for each cylinder, an air inlet ineach crankechamber, and a connecting rod in each crank-chamber adapted to seal that part of the chamber having the air inlet from the balance of the chamber and from the cylinder during a part of each cycle.

JOHN HARLIN GEISSE. 

